WO1996023027A1

WO1996023027A1 - Rubber composition and process for preparing the same

Info

Publication number: WO1996023027A1
Application number: PCT/JP1996/000114
Authority: WO
Inventors: Yukio Takagishi; Masao Nakamura
Original assignee: Nippon Zeon Co., Ltd.
Priority date: 1995-01-23
Filing date: 1996-01-23
Publication date: 1996-08-01
Also published as: EP0806452A1; JP3488926B2; EP0806452A4; US6057397A

Abstract

A silica-containing diene rubber composition which is excellent in rebound resilience inductive of rolling resistance and has tensile strength and abration resistance equal or superior to those of carbon-black-containing diene rubber compositions and, further, good processability and hardness properties. The composition is characterized in that the diene rubber component is a hydroxylated diene rubber having a weight-average molecular weight of not less than 50,000 or a blend thereof with other diene rubber(s). Such a rubber composition is prepared by a process characterized in that either the hydroxylated diene rubber or the blend thereof is used as the diene rubber component and at least part of the necessary silica is mixed with the diene rubber component to prepare a mixture, which is then mixed with the rest of the silica and other compounding ingredients.

Description

Rubber composition and method for producing the same

Technical field

The present invention relates to a rubber composition obtained by compounding silica as a reinforcing agent with a gen-based rubber. More specifically, the present invention relates to a silica-containing gen-based rubber composition having excellent rebound resilience and excellent tensile properties, wear properties, hardness properties and processability, and a method for producing the same.

Background art

In recent years, with the emphasis on resource saving and environmental measures, the demand for lower fuel consumption of automobiles has become increasingly severe. Contributing to lower fuel consumption of automobile tires by reducing rolling resistance Is required. In order to reduce the rolling resistance of a tire, a rubber material capable of providing a vulcanized rubber having high rebound resilience is generally used as a rubber material for a tire.

Hitherto, it has been proposed to increase the rebound resilience by using a rubber composition obtained by compounding a sili force instead of carbon black as a reinforcing agent with a gen-based rubber as a rubber material for tires. However, the silicone rubber compounded gen-based rubber composition has the carbon black compounded gen-based rubber composition.

There was a problem that sufficient abrasion resistance and tensile strength could not be obtained as compared with 20 products. It is thought that one of the causes is that silica has a lower affinity for gen-based rubber than carbon black, and thus cannot exhibit a sufficient reinforcing effect.

Conventionally, in order to increase the affinity between silica and gen-based rubber, It has been studied to use a gen-based rubber into which a substituent having a compatibility is introduced. For example, in the case of a gen-based rubber prepared by an emulsion polymerization method, a gen-based rubber having a tertiary amino group introduced therein (Japanese Patent Application Laid-Open No. H11-111444) is used. In the above, an alkylsilyl group (Japanese Patent Application Laid-Open No. 1-188501), a halogenated silyl group (Japanese Patent Application Laid-Open No. 5-230286) or a substituted amino group (Japanese Patent Application Laid-Open No. -No. 2 920) has been proposed.

However, many of the gen-based rubbers with these substituents are strongly agglomerated with silica when mixed with silica, causing poor dispersion, resulting in poor processability and hardness properties, rebound resilience, and tensile strength. It also has the disadvantage that its properties such as wear resistance are not sufficiently improved.

Disclosure of the invention

An object of the present invention is to provide a silica-containing gen-based rubber composition, which has excellent rebound resilience as an index of rolling resistance, and has a tensile strength and resistance equivalent to or higher than that of a gen-based rubber composition containing carbon black. It is an object of the present invention to provide a composition which exhibits abrasion and has good workability and hardness characteristics.

The inventors of the present invention have conducted intensive studies to overcome the problems of the prior art, and as a result, as a gen-based rubber component reinforced with silica, less of a hydroxyl group-containing gen-based rubber having a weight average molecular weight of 500,000 or more. By using at least one of them, or by using a combination of at least one of the hydroxyl group-containing rubbers with another rubber, excellent workability and hardness characteristics, high rebound resilience and sufficient It has been found that a rubber composition exhibiting excellent tensile strength and abrasion resistance can be obtained.

When the components are mixed to produce the rubber composition of the present invention, After mixing the system rubber component and all or part of the required amount of silica, if there is residual silica, a reinforcing agent such as carbon black, clay, talc, etc., together with the residual silica, vulcanizing agent By adding and mixing an anti-aging agent, a plasticizer, and other compounding agents, it was found that the processability was further improved and the vulcanized rubber properties were also improved.

The present invention has been completed based on these findings. Thus, according to the present invention, in a rubber composition containing a gen-based rubber component and a silicic acid as a reinforcing agent, the gen-based rubber component has a hydroxyl group-containing gen-based compound having a weight average molecular weight of 500,000 or more. A rubber composition characterized by being a rubber (A) or a blend of the hydroxyl group-containing gen-based rubber (A) and another gen-based rubber (B).

Further, according to the present invention, in a method for producing a rubber composition by mixing a gen-based rubber component, silica as a reinforcing agent and other compounding agents, the gen-based rubber component has a weight average molecular weight of 50, Use of a hydroxy group-containing gen-based rubber (A) of not less than 000 or a combination of the hydroxy group-containing gen-based rubber (A) and another gen-based rubber (B); Mixing at least a part of a required amount of silica with the gen-based rubber component, and then mixing the obtained mixture with a residual amount of silica and other compounding agents.

Hereinafter, the present invention will be described in detail.

Hydroxyl-containing gen-based rubber (A)

In the present invention, as the gen-based rubber component, a hydroxyl-containing gen-based rubber (A) having a weight average molecular weight of 50,000 or more is used, or the hydroxyl-containing gen-based rubber (A) and another gen-based rubber are used. Used together with (B). The hydroxyl group-containing gen-based rubber (A) can be used in combination of two or more kinds. Two or more other gen-based rubbers (B) may be used in combination. <The weight-average molecular weight of the hydroxyl-containing gen-based rubber (A) is the weight in terms of standard polystyrene measured by gel permeation chromatography (GPC). It has a weight average molecular weight (Mw) of 50,000 or more, preferably 100,000 to 1,000,000, more preferably 100,000 to 800,000. If the weight average molecular weight is too small, sufficient rebound resilience and abrasion resistance cannot be obtained.

The hydroxyl group in the hydroxyl group-containing rubber (A) may be a primary, secondary or tertiary hydroxyl group. However, the effect of improving rebound resilience, abrasion resistance, tensile strength, etc., is at a higher level. To achieve this, primary or secondary hydroxyl groups are preferred, with primary hydroxyl groups being particularly preferred.

Examples of the hydroxyl group-containing rubber (A) include a copolymer of a hydroxyl group-containing vinyl monomer and a conjugated gen monomer, or a copolymer of a hydroxyl group-containing vinyl monomer and a conjugated gen monomer and another copolymer. A copolymer with a polymerizable monomer can be used. The hydroxyl group-containing gen-based rubber (A) also includes a polymer of a conjugated gen-based monomer or a copolymer of a conjugated gen-based monomer and another copolymerizable monomer, and By reacting the (co) polymer having a bound active metal with at least one compound (modifier) selected from ketones, esters, aldehydes and epoxies, Co) A polymer having a hydroxyl group introduced into the polymer may be used.

The method for producing the hydroxyl group-containing gen-based rubber (A) includes (1) primary, A method of copolymerizing a vinyl monomer having a secondary or tertiary hydroxyl group with a conjugated monomer or a conjugated monomer and another copolymerizable monomer (copolymerization method) , And (2) polymerizing a conjugated gen monomer or copolymerizing a conjugated gen monomer with another copolymerizable monomer to have an active metal bound in the molecule A gen-based polymer is prepared, and then the gen-based polymer is reacted with a modifying agent such as ketones, esters, aldehydes and epoxies to form a primary, secondary or A method (modification method) of introducing a tertiary hydroxyl group into the gen-based polymer is exemplified.

The hydroxyl group-containing rubber (A) used in the present invention is a conjugated rubber having at least one hydroxyl group in the molecule. When the hydroxyl group-containing gen-based rubber (A) is produced by the copolymerization method of the above (1), usually, 0.05 to 30% by weight of a hydroxyl group-containing vinyl monomer, a conjugated gen-based monomer Each monomer is mixed so as to have a content of 40 to 99.5 wt% and other copolymerizable monomers of 0 to 59.5 wt% (based on the amount of binding). Polymerize. In the case where the hydroxyl group-containing rubber (A) is produced by the modification method (2), for example, an active metal-containing initiator is usually used, and the co-gen monomer is usually 40 to 100% by weight. % And other copolymerizable monomers. Each monomer is (co) polymerized so as to have a content of 0 to 60% by weight (based on the amount of binding), or a conjugated monomer. After preparing a gen-based polymer containing 40 to 100% by weight and 0 to 60% by weight of other copolymerizable monomers, the polymer is reacted with an active metal-containing initiator to form an active metal. The metal is bound and then denatured with a denaturant.

Examples of conjugated diene monomers include 1,3-butadiene and 2-methadiene. Chill-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and the like. Among these, 1,3-butadiene, 2-methyl-1,3-butadiene and the like are preferable, and 1,3-butadiene is more preferable. The conjugated gen-based monomers can be used alone or in combination of two or more.

The other copolymerizable monomer is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene monomer and does not impair the intended properties. Aromatic vinyl monomers are preferably used. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, , 4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, monofluorostyrene and the like are exemplified. Among them, styrene is preferred.

The microstructure in the conjugated gen part of the hydroxyl group-containing gen-based rubber (A) is not particularly limited, and is appropriately selected depending on the purpose of use. The content of the vinyl group (1,2-vinyl group and 3,4-vinyl group) in the conjugated part is, for example, in the range of 10 to less than 30% when it is desired to improve the rebound resilience and abrasion resistance. In order to improve wet skid resistance, it is preferable to select a value within the range of 30 to 90%.

When the hydroxyl group-containing gen-based rubber (A) contains an aromatic vinyl monomer unit (aromatic vinyl unit), the chain distribution of the aromatic vinyl unit is not particularly limited, but one aromatic vinyl unit is used. Is usually independent chain content It is at least 40% by weight, preferably at least 50% by weight, more preferably at least 55% by weight of the amount of the bound aromatic vinyl, and the content of the long chain having at least 8 aromatic vinyl units is usually The amount is preferably 5% by weight or less, more preferably 2.5% by weight or less, more preferably 1.5% by weight or less of the amount of the bound aromatic vinyl, such as rebound resilience, abrasion resistance, wet skid resistance, etc. It is desirable to achieve a high balance of such characteristics.

To produce the hydroxyl group-containing rubber (A) by the copolymerization method (1), a vinyl monomer having a hydroxyl group [i] and a conjugated diene monomer [ii] or a conjugated diene rubber are used. A copolymer is produced from the monomer [ii] and the copolymerizable monomer [iii]. The content of each monomer unit in the copolymer is appropriately selected according to the required properties, but the ratio of the unit [i], the unit [ii] and the unit [iii] is Usually, [0.05 to 30% by weight]: [40 to 99.95% by weight]: [0 to 59.95% by weight], preferably [0.1 to 20% by weight: [50 to 90% by weight]: [9.9 to 49.9% by weight], more preferably [0.3 to: 15% by weight]: [60 to 85% by weight]: [14.7 to 39.7% by weight] . If the content of the hydroxyl group-containing vinyl monomer [i] is too small, it is difficult to obtain a sufficient improvement effect, and if it is too large, the balance between processability and rebound resilience is reduced. However, neither is preferred. The conjugated monomer [ii] and other copolymerizable monomers [iiii] used in this method are as described above.

As the hydroxyl group-containing vinyl monomer, a polymerizable monomer having at least one primary, secondary or tertiary hydroxyl group in one molecule is used. Such hydroxyl group-containing vinyl monomers include, for example, Unsaturated carboxylic acid monomers containing a vinyl group, vinyl ether monomers, aromatic vinyl monomers, and vinyl ketone simple monomers. Dimers are preferred. Examples of the hydroxyl-containing unsaturated carboxylic acid-based monomer include, for example, acrylic acid,

5 Esters of unsaturated carboxylic acids such as lylic acid, itaconic acid, fumaric acid, and maleic acid, and derivatives such as amides and acid anhydrides, and preferably acrylate esters and methacrylic acid. Acid esters and the like. Specifically, hydroxymethyl (meth) acrylate, 2-hydroxyshethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate ) Acrylate, 3-chloro-1-hydroxypropyl (meth) acrylate, 3-phenoxy-1-hydroxypropyl (meth) acrylate, glycerol mono (meta) acrylate Acrylate, hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxyquinpropyl (meth) acrylate, hydroxyhexyl (meth) acrylate

15 5) Acrylate, hydroxyoctyl (meth) acrylate, hydroxymethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide , 3-hydroxypropyl (meth) acrylamide, G (ethylene glycol) itacone, di (propylene glycol) itacone, bis

20 (2-Hydroxypropyl) itaconate, bis (2-hydroxyxethyl) itaconate, bis (2-hydroxyxethyl) fumarate, bis (2-hydroxyxethyl) malate, 2-hydroxyxyl vinyl ether, hydroxymethyl bi Dilketone, aryl alcohol and the like are exemplified. Preferred are hydroxymethyl (meth) acrylate, 2- Hydroxyshetyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 31-phenoxy1-2-hydroxypropyl (meth) acrylate, glycer Roll mono (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl

(Meth) acrylate, hydroxymethyl (meth) acrylamide, 21-hydroxyl (meth) acrylamide, 2-hydroxypropyl

Examples thereof include (meth) acrylamide and 3-hydroxypropyl (meth) acrylamide. Among them, particularly preferred are hydroxymethyl (meth) acrylate, 2-hydroxyshethyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. These hydroxyl group-containing vinyl monomers can be used alone or in combination of two or more.

In producing the hydroxyl group-containing gen-based rubber (A) by the copolymerization method (1), the polymerization method is not particularly limited, but usually an emulsion polymerization method is employed. The emulsion polymerization method may be a conventional emulsion polymerization method.For example, a method in which a predetermined amount of each of the above monomers is emulsified and dispersed in an aqueous medium in the presence of an emulsifier, and emulsion polymerization is performed using a radical polymerization initiator. No.

As the emulsifier, for example, a long-chain fatty acid salt having 10 or more carbon atoms and / or a rosinate are used. Specific examples include potassium salts such as cabric acid, lauric acid, myristic acid, palmitic acid, oleic acid, and stearic acid, and sodium salts.

Examples of the radical polymerization initiator include a persulfate such as ammonium persulfate and persulfate permeate; a combination of ammonium persulfate and ferric sulfate. Redox initiators such as combinations of organic peroxides with ferric sulfate, and combinations of hydrogen peroxide with ferric sulfate; and the like.

A chain transfer agent can be added to adjust the molecular weight of the copolymer.

6 I can. As the chain transfer agent, for example, mercaptans such as t-dodecylmercaptan, n-dodecylmerbutane, carbon tetrachloride, thioglycolic acid, diterpenes, terpinolene, water terpinenes and the like can be used.

The temperature of the emulsion polymerization can be appropriately selected depending on the kind of the radical polymerization initiator used, but is usually from 0 to 10 ° C, preferably from 0 ° C to

6 0 The polymerization mode may be either continuous polymerization or batch polymerization.

As the conversion of emulsion polymerization increases, a tendency to gel is observed. For this reason, the polymerization conversion is preferably suppressed to 80% or less, and it is particularly preferable to suppress the polymerization within the range of 40 to δ0 to 70%. The termination of the polymerization reaction is usually performed by adding a polymerization terminator to the polymerization system when a predetermined conversion is reached. As the polymerization terminator, for example, an amine compound such as getyl hydroxysylamine ァ hydroxylamine, a quinone compound such as hydroquinone or benzoquinone, sodium nitrite,

20 Sodium mushy carbamate, etc. are used.

After the emulsion polymerization reaction is stopped, unreacted monomers are removed from the obtained polymer latex as necessary, and then, if necessary, an acid such as sulfuric acid, sulfuric acid, etc. is added and mixed to determine the latex content. After adjusting to the value of, a salt such as sodium chloride, calcium chloride, potassium chloride, etc. is added as a coagulant. The mixture is mixed and coagulated as a crumb. The crumb is washed, dehydrated, and then dried with a band dryer or the like, whereby the desired hydroxyl group-containing diene rubber (A) can be obtained.

The hydroxy group-containing rubber (A) is produced by the modification method of the above (2).

First, a gen-based rubber containing an active metal bonded to a molecule is first produced, and then the gen-based rubber is modified by reacting with a modifier to introduce a hydroxyl group. The amount of the conjugated diene monomer in the diene rubber is usually

40 to: L 00% by weight, preferably 50 to 90% by weight, more preferably 60 to 85% by weight, and the amount of other copolymerizable monomers is usually to 0 to 60% by weight, preferably 10 to 50% by weight, more preferably 15 to 50% by weight

It is in the range of 40% by weight.

As the active metal, those generally known in the technical field of gen-based rubber may be used. For example, JP-A-58-166204, JP-A-61-425 Lithium, sodium, potassium, rubidium, cesium, etc. described in Japanese Patent Publication No. 52, Japanese Patent Publication No. 5-38041, and Japanese Patent Application Laid-Open No. Sho 63-is 294,003. Alkali earth metals such as beryllium, magnesium, calcium, strontium, barium, etc .; Lanthanide series rare earth metals such as lanthanum, neodymium, etc. . Among these, alkali metals

20 and alkaline earth metals are preferred, and alkali metals are particularly preferred.

Gen-based rubber to which an active metal is bound is prepared by using an active metal-based catalyst as an initiator to form a solution of a conjugated gen monomer or a conjugated gen monomer and another copolymerizable monomer. It can be produced by polymerizing according to a polymerization method (JP-A-58-166604). Also other As a method, a gen-based polymer is produced by various polymerization methods (emulsion polymerization method, solution polymerization method, etc.), and then an active metal is added to the gen-based polymer chain by a post-reaction (Japanese Patent Laid-Open No. 58-189,203). However, it is not limited to these methods.

As the active metal base catalyst (active metal-containing initiator), an organic alkali metal catalyst, an organic alkaline earth metal catalyst, an organic lanthanide series rare earth metal catalyst and the like are used.

Examples of the organic alkali metal catalyst include, for example, organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium: dilithiummethane, 1,4-dilithiobutane, Polyfunctional organic lithium compounds such as 1,4-diethyl-1-ethyl ethyl hexane and 1,3,5-trilithobenzene; sodium naphthalene, potassium naphthalene, and the like. Among these, an organic lithium compound is preferable, and an organic monolithium compound is particularly preferable.

Organic alkaline earth metal catalysts include, for example, n-butylmagnesium, n-hexylmagnesium, ethoxycalcium, stearylate, t-butoxystrontium, ethkinbarium, isopropoxybarium, ethyl mercaptobarium , T-butoxybarium, phenoxybarium, getylaminobarium, barium stearate, ethylvalium and the like.

Examples of the organic lanthanide series rare earth metal catalyst include, for example, neodymium triethylaluminum versatate / ethylaluminum sesquioxide as described in JP-B-63-644444. Consists of Composite catalysts and the like are included.

These active metal-containing initiators can be used alone or in combination of two or more. In the case of the solution polymerization method (anion polymerization method), the amount of the active metal-containing initiator used depends on the type of the initiator or the required amount.

It is appropriately selected depending on the molecular weight of the resulting polymer, and is usually in the range of 1 to 20 millimoles, preferably 2 to 15 millimoles, more preferably 3 to 10 millimoles per kg of the generated rubber. .

The anion polymerization using the above-mentioned initiator is performed in a hydrocarbon-based solvent which does not break the initiator. Suitable hydrocarbon solvents include ordinary anion

It is not particularly limited as long as it is used for polymerization. For example, aliphatic hydrocarbons such as n-butane, n-pentane, iso-pentane, n-hexane, n-heptane, iso-octane and the like Alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane and the like: aromatic hydrocarbons such as benzene and toluene; and the like, preferably to n- Xane, cyclohexane, benzene and the like. If necessary, unsaturated hydrocarbons having low polymerizability such as 1-butene, cis-1-butene, 2-hexene and the like may be used. These hydrocarbon solvents are used singly or in combination of two or more, and are usually used in a ratio such that the monomer content becomes 1 to 30 weight.

20 In order to adjust the microstructure of the conjugated gen monomer unit or the distribution of the aromatic vinyl monomer to be copolymerized with the conjugated gen monomer in the copolymer chain during the anion polymerization reaction. , Tetrahydrofuran, getyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, Ethers such as dimethylene glycol dibutyl ether, etc .: Tertiary amide compounds such as tetramethylethyleneamine, trimethylamine, triethylamine, pyridine, quinuclidine, etc .; potassium-t-amyloxide, potassium-t A polar compound such as a metal alkoxide compound such as t-butyl oxide; a phosphine compound such as triphenylphosphine; may be added to the reaction system. These polar compounds are used alone or in combination of two or more, and the amount of use is usually 0 to 200 mol per 1 mol of the initiator.

The anion polymerization reaction is usually carried out in a batch or continuous polymerization mode at a temperature in the range of 178 to 150 ° C. In the case of copolymerizing an aromatic vinyl monomer, in order to improve the randomness of the aromatic vinyl unit, for example, JP-A-59-14021 and JP-A-56- According to the method disclosed in JP-A-143209, the conjugated gen is adjusted so that the ratio of the aromatic vinyl monomer and the conjugated gen-based monomer in the polymerization system falls within a specific range. It is desirable to continuously or intermittently supply a system monomer or a mixture of a conjugated diene monomer and an aromatic vinyl monomer to the reaction system.

Specific examples of the polymer produced by anion polymerization include polybutadiene, polyisoprene, butadiene-isoprene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-isoprene copolymer, and the like. Can be exemplified. Thus, a conjugated gen-based polymer having an active metal bonded to the terminal of the polymer chain (hereinafter, referred to as an active polymer) is obtained.

In a method of adding an active metal in a post-reaction (post-addition reaction of an active metal), for example, an equimolar amount of methanol or isopropanoate to the active polymer is used. After the polymerization reaction is stopped by adding an alcohol such as alcohol, the active metal is added by newly adding an active metal-containing initiator and, if necessary, the polar compound. The reaction temperature is usually in the range of 78 to 150 ° C, preferably 20 to 100 ° C, and the reaction time is usually 0.1 to 24 hours, preferably 0.5 to 100 ° C. 4 hours range. Thus, an active polymer having an active metal bonded to the polymer main chain is obtained. Similarly, an active metal can be introduced into a molecular chain by reacting with an active metal-containing initiator using a conjugated gen-based polymer obtained by another method such as emulsion polymerization.

The modifier is not particularly limited as long as it can react with the active metal to form a hydroxyl group.Specifically, ketones, esters, aldehydes, epoxies and the like are used. Can be. Among these, epoxies having an epoxy ring structure at the molecular terminal are particularly preferable because they can generate a primary hydroxyl group. These denaturing agents can be used alone or in combination of two or more. Ketones include, for example, acetone, benzophenone, aminoacetone, aminobenzophenone, acetylacetone and the like. Examples of the esters include methyl acetate, methyl adipate, ethyl ethyl adipate, methyl methacrylate, and ethyl methacrylate.

Examples of the aldehydes include benzaldehyde, pyridine aldehyde, and the like.

Epoxy compounds include, for example, general formula (1)

(In the formula, and and R ₂ each independently represent a hydrogen atom or a hydrocarbon group which may have a substituent, and and and R ₂ may combine to form a cyclic structure. )

The compound represented by these is mentioned. Epoxies in which at least one of R and R _{2 in} formula (1) is a hydrogen atom are preferred. The number of carbon atoms of the hydrocarbon group which may have a substituent is usually 20 or less, preferably 1 to 10, more preferably 1 to 6 lower hydrocarbon groups. Specific examples of the hydrocarbon group which may have a substituent include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxyalkyl group, a dialkylaminoalkyl group, and a dialkyl group. Examples include a reelaminoalkyl group, a trialkoxysilylalkyl group, and a trialkylsilylalkyl group. Examples of the ring structure formed by combining R and R ₂ include a cycloalkyl group. Among these, an alkyl group, an alkenyl group, an aryl group, an alkoxyalkyl group, a dialkylaminoalkyl group, a diarylaminoalkyl group, a trialkoxysilylalkyl group, and a trialkylsilylalkyl group are preferable, and an alkyl group is particularly preferable. preferable.

Specific examples of epoxies include, for example, ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxy-iso-butane, 2,3-epoxybutane, 1,2-epoxyhexane , 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxytetrade Can, 1,2-epoxyhexadecane, 1,2-epoxyoctadecane, 1,2-epoxyeicosane, 1,2-epoxy-1-pentylpropane, 3,4-epoxy-1-butene, 1,2 —Epoxy-5-hexene, 1,2-epoxy-9-decene, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxycyclododecane, 1,2-epoxy Butylbenzene, 1,2-epoxy-1-methoxy-1-methylpropyl mouthpan, glycidyl methyl ether, glycidyl ethyl ether, glycidyl isopropyl ether, glycidyl aryl ether, glycidyl phenyl ether, glycidyl butyl ether, 2- ( 3,4-epoxycyclohexyl) ethyltrimethoxine or 3-glycidyloxypropyltrimethoxysilane . Among them, ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxyiso-butane, 2,3-epoxybutane, 1,2-epoxyhexane, 3, 4-epoxy-1-butene, 1,2-epoxy-5-hexene, glycidylmethylether, glycidylethylether, glycidylisopropylether, glycidylarylether, glycidylphenylether, glycidylbutylether, 3-glycidyloxy Propyltrimethoxysilane and the like are preferred, and terminal epoxy compounds such as ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxy-iso-butane, and 1,2-epoxyhexane are particularly preferred.

Epoxies also include ephalohydrins, ie, compounds in which at least one hydrogen atom of the above-mentioned epoxies has been replaced with a halogen atom. Preferred examples of ephalohydrins and examples of hydrocarbon groups Is the same as the above epoxies. Specifically, for example, epichlorohydrin, moebulin in the mouth of eviv, epiodohydrin, 2,3-epoxy—1,1,1,1-trifluorob bread, 1,2-epoxy-1H, 1H, 2 H, 3H, 3H-heptadecafluoroundecane and the like, preferably, epichlorohydrin and epibromohydrin.

The amount of the modifier used is appropriately selected depending on the type of the modifier and the required properties, but is usually 0.1 to 10 mol, preferably 0.5 to 5 mol, more preferably 1 to 1.5 mol per mol of active metal. Range.

The modification reaction is carried out by contacting the active polymer having an active metal bonded in the molecule with a modifier. When an active polymer is produced by anion polymerization, a modification reaction is usually performed by adding a predetermined amount of a modifier to the active polymer solution before the termination of the polymerization. In addition, both terminal modification and main chain modification may be performed. In this case, an active metal may be introduced into the main chain of the syngeneic polymer end-modified with a modifying agent, and further reacted with the modifying agent. The reaction temperature and reaction time in the denaturation reaction can be selected from a wide range, but are generally from room temperature to 120 and from several seconds to several hours.

The hydroxyl group-containing gen-based rubber (A) used in the present invention may be one produced by a method other than the above (1) and (2). For example, a method of introducing a hydroxyl group by reacting an epoxidized gen-based rubber with an alcohol (Japanese Patent Publication No. 60-53511), heating epoxidized polybutadiene in the presence of an amine and a carboxylic acid, A method of opening the epoxy ring (Japanese Patent Publication No. 60-53512, Japanese Patent Application Laid-Open No. 60-55004, and Japanese Patent Application Laid-Open No. 61-148205); Oxidation with hydrogen peroxide or the like to effect hydroxylation (Japanese Unexamined Patent Publication No. No. 04-174408) A method of hydrolyzing a halogenated butadiene-styrene rubber obtained by copolymerizing a halogen-containing monomer such as butadiene with one-neck under an alkaline condition (JP-A-3-174408) In the present invention, those produced by a known method such as that disclosed in Japanese Unexamined Patent Publication (KOKAI) can be used as the hydroxyl group-containing rubber (A).

Other Jen Rubber (B)

The hydroxyl group-containing rubber (A) can be used alone as a rubber component of the rubber composition of the present invention, but may be used in combination with other rubber (B). When other gen-based rubber (B) is used in combination, the proportion of phenol-containing gen-based rubber (A) in the gen-based rubber component is appropriately selected according to the application and purpose, but is usually 10% by weight or more. It is preferably in the range of 20-80% by weight. That is, (A) :( B) = 10-100: 90-0, preferably 20-80: 20-80, and more preferably 30-70: 70-30 (weight ratio). If the proportion of the hydroxyl group-containing gen-based rubber (A) is too small, a sufficient modifying effect cannot be obtained, which is not preferable.

Other gen-based rubbers (B) include, for example, natural rubber (NR), polyisoprene rubber (IR), emulsion-polymerized styrene-butadiene copolymer rubber (SBR), solution-polymerized random SBR (bonded styrene amount 5 to 50% by weight, 1,2-bonding amount of butadiene unit 10-80%), trans SBR (70-95% of trans in butadiene part), low cis polybutadiene rubber (BR), high cis BR, high trans BR ( (Butadiene transance 70-95%), styrene-isoprene copolymer rubber (SIR), butadiene-isoprene copolymer rubber, solution-polymerized random styrene Tajene soprene copolymer rubber (SIBR), emulsion polymerization SIBR, emulsion polymerization styrene-acrylonitrile-butadiene copolymer rubber, acryloyl nitrile-butadiene copolymer rubber, high vinyl SBR—low vinyl SBR rubber Copolymer rubber, polystyrene-polybutadiene-polystyrene block

₅ click copolymer rubber and the like, can be appropriately selected according to the required characteristics. These gen-based rubbers can be used alone or in combination of two or more. Among these, NR, BR, IR, SBR, SIBR and the like are preferable, and from the viewpoint of workability, NR and IR are particularly preferable.

When a hydroxyl group-containing rubber (A) is used in combination with another gen rubber (B) as the ID gen rubber component, the gen rubber component is [hydroxyl group containing rubber (A)]: [ NR and / or IR] = 20-80: 80-20, more preferably 30-70: 70-30 (weight ratio), or [hydroxyl-containing gen-based rubber (A)]: _ls [NR and Z or IR]: [S BR] = 80 to 20: 10 to 70: 10 to 70 (overlap ratio).

Siri force

The sili force used in the present invention is one generally used for compounding general-purpose rubber. Specific examples include dry-process white carbon, wet-process white carbon, colloidal silica, and precipitated silica disclosed in JP-B-62-62838, which are generally used as a reinforcing agent. It is a wet-process white carbon mainly composed of hydrous gay acid.

Silica is preferably in the acidic region in order to improve dispersibility. Silica treated with a cutting agent or the like can also be used. The specific surface area of silica is not particularly limited, usually, 50 to 400 111 ² 8, preferably more preferably from 100 to 250,111 ² 8 :, range of 120 to 190 m ² Zg. If the specific surface area is excessively small, the reinforcing property is inferior. Conversely, if the specific surface area is excessively large, the workability is inferior, and the abrasion resistance and rebound resilience are not sufficiently improved.

The use ratio of silica is not particularly limited, but is usually 20 to 150 parts by weight, preferably 40 to 120 parts by weight, based on 100 parts of the gen-based rubber component. If the use ratio of the sili force is excessively small, the reinforcement is inferior. On the other hand, if the ratio is excessively large, the viscosity of the unvulcanized rubber composition increases, resulting in poor processability.

As the coupling agent, a silane coupling agent can be preferably used. Various known silane coupling agents can be used. Typical examples thereof include 7-mercaptopropyltrimethoxysilane (A 189; manufactured by Union Carbide Co., Ltd.) and 7-aminobutamate. Examples include built-in ethoxysilane (A1100: manufactured by Union Carbide) and bis [31- (triethoxysilyl) propyl] tetrasulfide (Si-69; manufactured by Degussa). The use ratio of the silane coupling agent is usually 0.01 to 30 parts by weight, preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the rubber component.

Rubber composition

The rubber composition of the present invention can be obtained by kneading each component according to a conventional method. The rubber composition of the present invention comprises, in addition to the gen-based rubber component and silica, other compounding agents such as a vulcanizing agent, a vulcanization accelerator, an antioxidant, a plasticizer, a lubricant, a filler, and the like according to a conventional method. Each can contain the required amount O

These compounding agents are widely used in the rubber industry, and include, for example, vulcanizing agents such as sulfur and peroxyside: vulcanization accelerators such as thiazole, thiuram, sulfonamide, and guanidine. Vulcanization aids such as stearic acid, zinc white, etc .; power-supplying agents such as silane-based power-supplying agents; activators such as diethylene glycol, polyethylene glycol and organic silica compounds; FEF, HAF Reinforcing agents such as grades of carbon black, calcium carbonate, etc., grades of carbon black, ISAF, SAF, etc .; Plasticizers; Fillers, such as thermal black, acetylene black, graphite, clay, talc, etc .; Oils and the like. From these various compounding agents, the necessary compounding agent can be appropriately selected according to the purpose and application.

When kneading each component, first, a gen-based rubber component and silica are mixed using a mixer such as a roll, Banbury, and the like, and then, if other compounding agents are added and mixed, dispersibility is improved. A rubber composition having better properties can be obtained. In this case, the silica may be added all at once, but if the predetermined amount is added preferably in two or more portions, the dispersion becomes easier and the mixing of the silica and the gen-based rubber component becomes easier. For example, 10 to 90% by weight of the total amount of silica can be added in the first time, and the remainder can be added in the second and subsequent times.

Among the other compounding agents mentioned above, the silane coupling agent and the activator may be added as needed at the time of the initial mixing of the gen-based rubber component and the silicic acid. However, it is preferable to add it in the subsequent steps. When mixing the first gen-based rubber component with silica, silane-based Addition of a compounding agent other than the activating agent or the activator increases the mixing time and may reduce the reinforcing properties of silica.

The temperature for mixing the diene rubber component and silica is usually 80 to 2

0 0 ^, preferably 100 to 190, more preferably 140 to 180 ° C. If the temperature is excessively low, the improvement in wear characteristics is small, and if it is excessively high, the gen-based rubber component is burned. The mixing time is usually 30 seconds or more, preferably 1 to 30 minutes.

Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, the tensile strength and abrasion resistance, which have been disadvantages hitherto, can be significantly improved without impairing the rebound resilience characteristic of the silica-containing rubber composition, and the hardness is high. A rubber composition having excellent properties and processability is provided. The rubber composition of the present invention can be used in various applications, for example, as a raw material for producing automobile tires, automobile parts, hoses, window frames, belts, shoe soles, anti-vibration rubbers, etc. , High impact polystyrene,

It can be used as a reinforcing rubber for resins such as ABS resin.

The rubber composition of the present invention is particularly excellent as a rubber material for tread in fuel-efficient tires, and is also suitable for all season tires, high-performance tires or studless tires. It can also be suitably used as a rubber material for a metal, a carcass, a beat portion and the like.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples. Parts and percentages in these examples are by weight unless otherwise specified. T / 6/00114

twenty four

It is a standard.

The measurement of various physical properties and the micro-mouth structure of the polymer was performed according to the following methods.

(1) The amount of bound styrene in the polymer and the amount of vinyl bound in the butadiene portion were measured by infrared spectroscopy (Hampton method).

(2) The amount of hydroxyl group-containing monomer in the polymer is determined by ¹³ C-NMR spectrum after treating the polymer with phenyl isocyanate according to the method described in JP-A-3-174408. It was calculated by quantifying the phenyl group of the diisocyanate.

(3) The molecular weight of the polymer was measured by GPC and expressed as a weight average molecular weight in terms of standard polystyrene.

(4) The styrene chain distribution was determined by ozonolysis of the polymer according to the method described in the Proceedings of the Society of Polymer Science, Vol. 29, No. 9, page 2055, followed by GPC measurement. The amount of chains and the amount of long chains in which eight or more styrene units were linked were calculated.

(5) The rebound resilience was measured at 60 using a Lupke rebound resilience tester according to JIS K 6301.

(6) Abrasion resistance was measured using a pico abrasion tester according to ASTM D-2228. This property is expressed as an index (pico wear index).

/ ο

(7) Mooney viscosity was measured according to JIS K6301.

(8) The workability was evaluated based on the following criteria by observing the winding property around the roll.

◎: Wrap neatly, 〇: Slightly lift, △: Winding force, float Frequently rising, X: hardly wraps.

[Production Example 1] (Copolymerization method)

In a tank equipped with a stirrer, 200 parts of water, 3 parts of rosin stone, 0.2 part of t-dodecyl mercaptan, and monomers having the composition shown in Table 1 were charged. The reactor temperature was set to 5, and 0.1 parts of cumene hydroperoxide, 0.2 parts of sodium formaldehyde, sulfoxylate and 0.01 part of ferric sulfate were added as radical polymerization initiators. The polymerization was started. When the conversion reached 60%, the reaction was stopped by the addition of getylhydroxylamine. Next, the unreacted monomer was recovered, and the polymer was coagulated with sulfuric acid and a salt to form a crumb. After drying the crumb with a crumb dryer, gen-based rubber Nos. 1 to 8 were obtained. Table 1 shows the properties of the polymer.

Gen-based rubber No. 1 2 3 4 5 6 7 8 Butadiene charge (parts) 69 69 69.7 69 70 69 69 71 Styrene charge (parts) 28 28 30 28 20 28 28 29

HA (1) preparation amount (parts) 3---one---

HEA (2) charge (parts)-3------

HEMA (3) charge (parts)--0.3 3 10---

G0HMA (4) Amount (parts)-----3--

DMAPAA (5) Amount (parts)------3-Bound styrene amount (wtX) 20.7 20.1 23.2 20.8 14.0 21.3 21.3 23.2 Bound HA (1) amount (wtX) 4.8-1-----Bound HEA (2) Amount (wtX)-5.3------Combined HEMA (3) Amount OtX) 0.5 3.7 11.5

Bound G0HMA (4) amount (wtX) 2.6

Bound DMAPAA (5) amount (wtX) 2.6 Weight average molecular weight (Mwx 10) 44.8 42.2 43.6 46.9 47.3 45.2 44.3 46.8

(Footnote)

(1) HA: 2—hydroxypropyl acrylate

(2) HE A: 2—Hydroxysche Acrylate

(3) HEMA: 2—Hydroquinethylate

(4) GOHMA: glycerol monomethacrylate

(5) DMA PAA: Dimethylami knob knob [Production Example 2] (Modification method: terminal modification)

In an autoclave equipped with a stirrer, 8000 g of cyclohexane, 400 g of styrene and 800 g of butadiene were added, and 10 mmol of tetramethylethylenediamine (TMEDA) and 10 mmol of n-butyllithium were further added. The polymerization was started at 40T). Ten minutes after the start of the polymerization, the remaining 800 g of butadiene was continuously added. After confirming that the polymerization conversion reached 100%, ethylene oxide (EO) was added in an equimolar amount to the polymerization active terminal (L i), and the mixture was reacted for 20 minutes. After completion of the reaction, 20 mmol of methanol was added as a terminator, 20 g of 2,6-di-tert-butylphenol to was added, and the polymer was recovered by a steam stripping method. Gen-based rubber No. 9 was obtained. Similarly, gen-based rubber Nos. 12 to 16 were obtained under the polymerization conditions described in Table 2, and the properties of these polymers are shown in Table 2. In addition, for gen-based rubber No. 15, aminostyrene (AST) was used as a modifier for generating an amino group.

15 [Production Example 3] (Modification method: main chain modification)

In an autoclave equipped with a stirrer, 8000 g of cyclohexane, 460 g of styrene and 700 g of butadiene were added, and 3.5 mmol of TMEDA and 11 mmol of n-butyllithium were added. The polymerization was started at 50 T; Ten minutes after the start of the polymerization, the remaining 840 g of butadiene was continuously added. Heavy

20 After confirming that the conversion was 100%, the polymerization was stopped by adding an equimolar amount of methanol to the active terminal (L i). To this solution, 60 millimoles of sec-butyllithium and 60 millimoles of TMEDA were added, and the mixture was reacted at 70 for 1 hour. Then, 60 millimoles of ethylene oxide (EO) was added, and the mixture was further stirred for 20 minutes. Add 120 mmol of methanol After stopping the reaction, the polymer was recovered in the same manner as in Production Example 2 to obtain gen-based rubber No. 10. Table 2 shows the properties of the polymer.

[Production Example 4] (Modification method: terminal modification + main chain modification)

In an autoclave equipped with a stirrer, 8000 g of cyclohexane, 310 g of styrene and 600 g of butadiene were added, and further 4 mmol of TME DA and 12 mmol of n-butyllithium were added. Polymerization was started at C. Ten minutes after the start of the polymerization, the remaining 1090 g of butadiene was continuously added. After confirming that the polymerization conversion rate reached 100%, an equimolar amount of propylene oxide (PO) was added to the active terminal (L i), and the reaction was carried out for 20 minutes. To this solution, 60 millimoles of sec-butyllithium and 60 millimoles of TMEDA were added, and the mixture was reacted at 70 ° C. for 1 hour. Then, 60 millimoles of ethylene oxide (EO) was added, and the mixture was reacted for 20 minutes. After the reaction was stopped by adding 120 mmol of methanol, a polymer was recovered in the same manner as in Production Example 2 to obtain a gen-based rubber No. 11. Table 2 shows the properties of the polymer.

Table 2

c footnote)

(*) Modifier:

EO: Ethylene oxide

PO: Propylene oxide

BPH: Benzofuunone

AST: Aminostyrene [Examples 1 to 6 and Comparative Example 1]

Using the gen-based rubber prepared in Production Example 1 as the raw material rubber and Ultrasil VN3G (manufactured by Degussa; specific surface area: 175 m ² Zg) as the silica, the experiment based on Formulation 1 shown in Table 3 was performed. Was performed as follows. First, in a Brabender type mixer with a capacity of 250 ml, as the first mixing operation, the total amount of raw rubber (100 parts) and a part of silica (35 parts) were mixed at 160 ° C for 2 minutes (sila). No second coupling agent was used), and then the second mixing operation consisted of the remaining silica (25 parts), plasticizer (10 parts), zinc white (5 parts), stearic acid (2 parts) and An antioxidant (1 part) was added and kneaded at the same temperature for 2.5 minutes. As a third mixing operation, the resulting mixture was mixed with sulfur (2 parts) and vulcanization accelerator (2 parts) together with 50 parts. Kneaded with an open roll. The obtained kneaded material was press-vulcanized at 160 ° C for 30 minutes to prepare a test piece, and each physical property was measured. Table 4 shows the results.

Table 3

(Footnote)

(1) Ultrasil VN3G (made by Degussa) or Nibucil AQ (made by Siri Riki)

(2) S i 69 (made by Degussa)

(3) Nocrack 6 C (Ouchi Shinkosha)

(4) Noxeller CZ (Ouchi Shinkosha)

Table 4

As is clear from the results in Table 4, the rubber composition (Example 16) using a hydroxyl group-containing gen-based rubber as the gen-based rubber component can be rolled without increasing the hardness and the compound viscosity. It can be seen that the workability is excellent and the tensile strength, rebound resilience, and wear resistance are sufficiently improved. In addition, the strength characteristics, rebound resilience, and elasticity of the case where the primary rubber having a hydroxyl group (Example 26) were used were higher than those of the secondary rubber having a hydroxyl group (Example 1). It can be seen that the effect of improving the wear characteristics is great.

[Example 79 and Comparative Example 24]

By performing experiments based on Formulations 1 and 2 shown in Table 3 in accordance with Example 1, the effects of the silane coupling agent, the kneading method, the type of silica, and the polar group (including hydroxyl group and Tertiary amino groups) were examined. In the case of Formulation 2, first, Raw material rubber (100 parts), silica (60 parts), plasticizer (100 parts), zinc white (5 parts), stearic acid (2 parts) and anti-aging agent (1 part) In a blender type mixer, knead with 160 ^ for 4.5 minutes, and then as a second mixing operation, mix the resulting mixture with sulfur (2 parts) and vulcanization accelerator (2 parts) for 50 minutes. The mixture was kneaded with an open roll at ° C. The resulting混棟product 1 6 0 3 0 min press vulcanized to prepare a test piece, the type of diene-based rubbers _c use in measuring the physical properties, the amount of the silane coupling agent, formulation , And the results are summarized in Table 5. In Table 5, the data of Example 4 in Table 4 was reprinted for comparison. Table 5

(Footnote)

(1) Silica:

V N: Ultrasil VN 3 G (made by Degussa)

AO: Nibusil AQ (Nippon Silica Co., Ltd.) From the results in Table 5, it was found that when a gen-based rubber having no hydroxyl group was used (Comparative Examples 2 and 3), even if 3 parts by weight of an expensive silane-based coupling agent was added, the rebound resilience was not sufficiently improved. Addition of 1 part by weight of the silane coupling agent shows almost no improvement effect. On the other hand, when a gen-based rubber containing 0.5% by weight of a monomer unit having a hydroxyl group is used (Example 7), the rebound resilience is significantly improved only by adding 1 part by weight of the silane coupling agent. This shows that properties such as tensile strength and abrasion resistance have been sufficiently improved.

As for the kneading method, first, the gen-based rubber and at least a part of the sily force are kneaded, rather than the method of kneading the gen-based rubber together with all the compounding agents other than sulfur and the vulcanization accelerator (formulation 2). Then, the method of mixing and kneading with the addition of compounding agents other than sulfur and the vulcanization accelerator (Formulation 1) shows that the effect of improving all the properties is higher than that of Example 4 and Example 8. You can see from the comparison. When the specific surface area of the silica compounded is less (specific surface area of the ultra Jill VN 3 G in Example 8 is 1 7 5 m ² Z g) is a specific surface area if not the magnitude (of the secondary Pushiru AQ in Example 9 The specific surface area is 200 m ² Zg), and the effect on the Mooney viscosity of the blend and the rollability is particularly large.

When a gen-based rubber having a tertiary amino group was used (Comparative Example 5), the rebound resilience and abrasion resistance were improved, but the blended Mooney was extremely high, and the workability, hardness properties, and tensile strength were high. It turns out that it is inferior.

[Examples 10 to 13 and Comparative Examples 5 to 6]

The same experiment as in Examples 1 and 8 was performed using the hydroxyl group-containing gen-based rubber produced by the solution polymerization method of Production Example 2. The type of jen rubber used Table 6 shows the types, formulation and results of Rica.

Table 6

(Footnote)

(1) Silica:

VN: Ultrasilil VN 3 G (made by Degussa)

AQ: Nibusil AQ (manufactured by Nippon Silica Co., Ltd.) From the results in Table 6, it can be seen that the difference in effect due to differences in the kneading method, the type of silica, and the polar group (hydroxyl group and tertiary amino group) of the gen-based rubber, It can be seen that this is the same as when the hydroxyl group-containing gen-based rubber produced by the polymerization method was used (see Table 5). In addition, the primary hydroxyl group-containing gen-based rubber modified with ethylene oxide (EO) is better than the tertiary hydroxyl-containing gen-based rubber modified with benzophenone (BPH) (Example 13). Rubber (Example 12) has a higher improvement effect under the same conditions. Karuru

[Examples 14 to 20 and Comparative Examples 7 to 8]

The same experiment as in Example 1 was performed using a blend of the gen-based rubber prepared in Production Examples 2 to 4 and natural rubber and / or polybutadiene (BR1220; manufactured by Zeon Corporation) as the raw material rubber. Was. Table 7 shows the composition of the raw rubber and the results. Table 7 Example Comparative example

14 15 16 17 18 19 20 7 8 Raw rubber

Gen-type rubber No. 9 70 30 1---50-1 Gen-type rubber No. 10 70

No thread rubber No. ll 70

Gen-based rubber No. 12 70

Gen-based rubber No. 13 70

Gen-based rubber No. 16 70

BR1220 30 70 Natural rubber 30 70 30 30 30 30 20 30 30 Tensile strength (Kg / cm ² ) 230 220 225 255 210 180 235 155 160 Elongation (X) 400 430 480 400 430 380 510 350 320 Hardness test (JIS ) 23 66 65 66 67 66 63 66 72 63 Rebound elasticity C 60T: 67 65 68 69 65 67 72 61 60 Pico abrasion index 115 108 125 145 110 165 125 105 122 Formulation ML, ₊₄ , 100 ° C 75 83 82 88 88 85 70 100 103 Roll formability ◎ ◎ 〇〇 ◎ 〇 ◎ 〇 X From the results shown in Table 7, when the hydroxyl group-containing styrene butadiene copolymer rubber and the natural rubber were used in combination (Examples 14 to 18), the styrene butadiene copolymer rubber having no hydroxyl group was combined with the natural rubber. Compared with the case of using it in combination (Comparative Example 7), the properties such as viscosity, hardness, tensile strength, rebound resilience, and abrasion resistance of the compound are sufficiently improved. It can be seen that when the hydroxyl group-containing styrene butadiene copolymer rubber having a high content of 1,2-vinyl group was used (Examples 14, 15, 18, and 20), the degree of improvement in processability was particularly high. . On the other hand, the conventional polybutadiene (BR1220) is inferior in processability and does not have sufficient physical properties when blended with natural rubber and silica (Comparative Example 8), but water modified by ethylene oxide It can be seen that by using an acid-containing polybutadiene rubber instead of BR 1220 (Example 19), the processability is improved, and the tensile strength, rebound resilience, and abrasion resistance are improved. Furthermore, it can be seen that the effect of improvement can be sufficiently exhibited also when a three-component rubber including a hydroxyl group-containing rubber, natural rubber, and polybutadiene rubber is used (Example 20).

Claims

The scope of the claims

1. In a rubber composition containing a gen-based rubber component and silica as a scavenger, is the gen-based rubber component a hydroxy-containing gen-based rubber (A) having a weight average molecular weight of 500,000 or more? Alternatively, a rubber composition characterized by being a blend of the hydroxyl group-containing gen-based rubber (A) and another gen-based rubber (B).

2. The hydroxyl group-containing rubber (A) is a copolymer of a hydroxyl group-containing vinyl monomer and a conjugated gen monomer, or a hydroxyl group-containing vinyl monomer and a conjugated gen monomer and other 2. The rubber composition according to claim 1, which is a copolymer with a copolymerizable monomer.

3. The content of the hydroxyl group-containing vinyl monomer, conjugated diene monomer and other copolymerizable monomers in the copolymer is 0.05 to 40% by weight and 40% respectively. 3. The rubber composition according to claim 2, wherein the amount is from 9 to 99.5% by weight, and from 0 to 59.95% by weight.

4. The hydroxyl group-containing vinyl monomer is at least selected from a hydroxyl group-containing unsaturated carboxylic acid monomer, a hydroxyl group-containing vinyl ether monomer, a hydroxyl group-containing aromatic vinyl monomer and a hydroxyl group-containing vinyl ketone monomer. 4. The rubber composition according to claim 2, which is one kind.

5. The rubber composition according to claim 4, wherein the hydroxyl group-containing vinyl monomer is a hydroxyl group-containing unsaturated carboxylic acid monomer.

6. The hydroxyl group-containing rubber (A) is a polymer of a conjugated monomer or a copolymer of a conjugated monomer and another copolymerizable monomer. A (co) polymer having an active metal bonded to a polymer and at least one selected from ketones, esters, aldehydes and epoxies 2. The rubber composition according to claim 1, wherein a hydroxyl group is introduced into the (co) polymer by reacting with one kind of compound.

7. The method according to claim 6, wherein the content of the conjugated diene monomer and the monomer copolymerizable therewith in the (co) polymer is 40 to 100% by weight and 0 to 60% by weight, respectively. Rubber composition.

8. The rubber composition according to any one of claims 2 to 7, wherein the copolymerizable monomer is an aromatic vinyl monomer.

9. The chain of the aromatic vinyl monomer in the hydroxyl group-containing gen-based rubber (A) is such that the content of the independent chain of one aromatic vinyl unit is at least 40% by weight of the amount of the aromatic vinyl unit. 9. The rubber composition according to claim 8, wherein the content of the long chain having eight or more aromatic vinyl units is distributed so as to be 5% by weight or less of the amount of the bound aromatic vinyl.

10. The rubber composition according to any one of claims 1 to 9, wherein the conjugated gen bond unit has a vinyl bond amount of less than 10 to 30%.

11. The rubber composition according to any one of claims 1 to 10, wherein the conjugated gen bond unit has a vinyl bond amount of 30 to 90%.

12. The rubber composition according to any one of claims 6 to 11, wherein the hydroxyl group is primary or secondary.

13. The rubber composition according to any one of claims 1 to 12, further comprising a silane coupling agent.

14. The rubber composition according to claim 13, wherein the amount of the silane coupling agent is 0.01 to 30 parts by weight based on 100 parts by weight of the rubber component.

15. The rubber set according to any one of claims 1 to 14, wherein the amount of silica is 20 to 150 parts by weight based on 100 parts by weight of the gen-based rubber component. Adult.

16. The rubber composition according to claim 15, which has a nitrogen adsorption specific surface area (BET method) of Siri force of 50 to 400 m ² g.

17. Nitrogen adsorption specific surface area of the silica (BET method) is a rubber composition in the range 16 according claims is 100 to 250 meters ^2.

18. The rubber composition according to claim 17, wherein the silica has a nitrogen adsorption ratio table (BET method) of 120 to 190 m ² Zg.

19. The rubber composition according to any one of claims 1 to 18, wherein the rubber composition is a tire rubber composition.

0 20. In a method of producing a rubber composition by mixing a gen-based rubber component, silica as a reinforcing agent and other compounding agents, the gen-based rubber component has a hydroxyl group content of at least 50.000 in weight average molecular weight. Use of a rubber-based rubber (A) or a combination of the hydroxyl-containing rubber-based rubber (A) and another rubber-based rubber (B), and at least one of a required amount of silica s Mixing a part of the mixture with the gen-based rubber component, and then mixing the obtained mixture with a residual amount of silica and other compounding agents. 0